. Electro-physiology. Electrophysiology. 386 ELECTRO-PHYSIOLOGY CHAP. a muscle rhombus, and it is tolerably accurate to say that the nerve-ending lies in the middle of each fibre (Fig. 121). But then it follows that all the points corresponding with the upper contacts (a, b), the thick part of the muscle, must be affected more, and earlier, by the waves of excitation from the nerve-endings (a, /3) than the lower ends of fibres, corresponding with the tendo achilles. Thus there will at first be a descending, and subse- quently a weaker ascending, current of action. " The upper half of
. Electro-physiology. Electrophysiology. 386 ELECTRO-PHYSIOLOGY CHAP. a muscle rhombus, and it is tolerably accurate to say that the nerve-ending lies in the middle of each fibre (Fig. 121). But then it follows that all the points corresponding with the upper contacts (a, b), the thick part of the muscle, must be affected more, and earlier, by the waves of excitation from the nerve-endings (a, /3) than the lower ends of fibres, corresponding with the tendo achilles. Thus there will at first be a descending, and subse- quently a weaker ascending, current of action. " The upper half of the muscle, on the contrary, should vary first in an ascending and then in a descending direction; here, however, the structure of the muscle is essentially different; the main part of the current (' Neigungstrorn') is prevented by the folds of the upper expansion from producing any ex- ternal effect, so that in the first place the abterminal phase of the upper half of the muscle is hardly per- ceptible, and in the second the upper tendon as a whole must be regarded as a lead-off from the longitudinal section. On leading off from both tendons, the effects are consequently not very dissimilar to those with the lead-off from belly and achilles tendon. There is thus no doubt that the first descending phase starts, not from the expansion of the tendo achilles, but from the longitudinal section, while the second ascending phase does originate at the achilles expansion" (Hermann). With the corrosion of the latter, the second phase naturally dies out, since the ends of fibres then become negative without it. And this of course applies to tetanus, in which du Bois-Eeymond first observed the descending effect in the currentless gastrocnemius, since, generally speaking, only the algebraic sum of the opposed action currents can be detected. But, owing to the preponderance of the first descending phase, the effect is actually descending. It is unnecessary here to enter into further m
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